Studies of AlN grown by MOVPE for electronic and optoelectronic applications [Elektronische Ressource] / by Sarad Bahadur Thapa

Informations

• Publié par: universitat_ulm
• Publié le: 01 janvier 2010
• Nombre de lectures: 34
• Langue: English
• Poids de l'ouvrage: 7 Mo

Extrait

Studies of AlN grown by MOVPE for
Electronic and Optoelectronic Applications
DISSERTATION
to obtain the academic degree of
DOKTOR-INGENIEUR
(DR.-ING.)
from the Faculty of Engineering and Computer Sciences
Ulm University
by
Sarad Bahadur Thapa
from Kathmandu, Nepal
Referees: Prof. Dr. Ferdinand Scholz
Prof. Dr. rer. nat. Albrecht Winnacker
Dean of the faculty: Prof. Dr.-Ing. Michael Weber
Ulm, 15 July 2010Acknowledgment
The work presented in this thesis has been carried out at the Institute of Optoelec-
tronicsandMicroelectronicsTechnologyCenterofUlmUniversityduring2005-2009. It
hasbeenaveryrewardingexperiencetobeamemberoftheGaNgroupledbyProf. Dr.
FerdinandScholz. Thisthesiswouldnothavepossiblewithoutthetrust,theguidance,
thesupportandthehelpfrommanypeopleinsideandoutsidetheuniversity.
Firstofall,IwouldliketoexpressmysinceregratitudetoProf. Dr. FerdinandScholz
for giving me the opportunity to do Ph.D. in his group. He has been a truly awesome
supervisor, continuously supportive, always providing invaluable advice and vision,
whileatthesametimegivingmefreedomtoexploremyownideas. Also,manythanks
tohimfortheintensivediscussionsandcorrectionstothiswork.
IwouldliketothankProf. Dr. rer. nat. AlbrechtWinnackerofthechairofMaterials
for Electronics and Energy Technology at the Department of Materials Science and
Engineering in the Friedrich-Alexander University of Erlangen-Nur¨ nberg for giving
hisvaluabletimeinmyPh.D.examinationasareferee.
I am grateful to Dr.-Ing. Christoph Kirchner, a former member of the GaN group,
forintroducingmetoMOVPEsystemattheMicroelectronicsTechnologyCenter. Ialso
thank him for carrying out RTA to some of my samples at the laboratory of Mattson
ThermalProductsGmbH,Dornstadt.
ItgavemeagreatpleasureforsharinganofficeroomwithDr.-Ing. JoachimHertkorn
at the institute in the period of my research work. We had a lot of fruitful discussions
on many aspects of academic, professional and private matters. Thanks Joachim for
creatingsuchacongenialatmosphereandyourwellunderstanding.
IhaveenjoyedthecompanyofallofmyfellowgroupmembersDipl.-Ing. Thomas
Wunderer,Dipl.-Phys. FrankLipski,Dipl.-Phys. StephanSchwaiger,M.Sc. Mohamed
Fikry,M.Sc. KamranForghani,Dr.-Ing. PeterBruk¨ ner,andDr.-Ing. BarbaraNeubert. I
particularlymissoureverydaylunchbreakandthecoffeechat. Thankyouverymuch
for sharing a wonderful time in all in- and outdoor activities during my stay there. It
wouldbeverydifficultformetoperformmanyofthetaskswithoutyourscientificand
technologicalcooperation.
I hold to warmly thank Dr. Jur¨ gen Ma¨ahn, Dipl.-Ing. Rainer Blood, Dipl.-Ing.
Rudolf Ro¨sch, Dipl.-Chm. Susanne Menzel, and Dipl.-Ing. Dieter Kinzler for their
technologicalsupportsinthecleanroom. Similarly,IwouldliketothankSuk¨ ranKilic
andHildegardMackforeasingtheadministrativeandbureaucraticprocedures.
I am highly grateful to Dr.-Ing. Fernando Rinaldi who helped me learning X-
ray measurements. I am indebted to Dipl.-Ing. Hendrik Roscher and PD Dr.-Ing.
Rainer Michalzik, former advisers of my master thesis work, for their continuous
support during my stay at the institute. I would like to thank all the colleagues and
the members of the institute for lending their helping hands whenever needed and
friendly accompanying on every occasions. I would like to mention especially two
research groups from Ulm University for an intense collaboration to carry out this
work. Without their contributions, this work would not have been realized. Many
thanks go to Dr. Gun¨ ther M. Prinz, Dipl.-Phys. Robert A. R. Leute, Dr. MartinFeneberg, and apl Prof. Dr. Klaus Thonke of the Institute of Semiconductor Physics
for CL, PL, and Raman investigations and Dipl.-Phys. Oliver Klein, Dr. Johannes
Biskupek, Dr. Andrey Chuvilin, Ms. Sabine Gro¨zinger, and Prof. Dr. Ute Kaiser of
TransmissionElectronMicroscopyGroupforTEManalysisofoursamples.
IwouldalsoliketothankDr. HongYinandProf. Dr. PaulZiemannoftheInstitute
ofSolidStatePhysics,andM.Sc. MohammedAlomariandProf. Dr.-Ing. ErhardKohn
of the Institute of Electron Devices and Circuits for providing us their lab facilities for
high temperature electrical measurements. I highly appreciate Mr. Alomari for his
endeavoronprocessingourstructuresforFETs. IamgratefultoDipl.-Ing. Alexander
MinkowoftheInstituteofMicroandNanomaterialsforSEMmeasurements.
I would like to thank Dr. Lutz Kirste, T. Fuchs, and M. Grimm of the Fraunhofer
Institute for Applied Solid State Physics, M. Trapp, P. Helm, and M. Gericke of RTG
Mikroanalyse GmbH, Berlin, and Dr. Christoph Schnuerer-Patschan and Dr. Ulrich
Ehrke of Cameca GmbH, Munich for SIMS measurements. A special thanks go to
PDDr. MatthiasBickermannoftheDepartmentofMaterialsScienceandEngineering
of the Friedrich-Alexander-University of Erlangen-Nur¨ nberg for providing the AlN
substrates. I am also grateful to Dietmar Schmitz of AIXTRON GmbH for providing
me an opportunity to learn MOVPE technology in the laboratory of AIXTRON at the
beginningofmyPh.D.work.
TheworkofmystudentsStefanWabra,HuWenjie,JunjunWang,LuXianming,and
EvangelosAngelopoulosarehighlyappreciated.
IhighlyacknowledgethefundingofDeutscheForschungsgemeinschaftandexpress
deep gratitude to Prof. Dr. Daniel Hofstetter of the Physics Institute of the University
of Neuchaˆtel for partly financially supporting through Sofja Kolajewskaja Program of
theAlexandervonHumboldtfoundation.
I feel a deep sense of gratitude for my parents and grand parents who formed part
of my vision and taught me the good things that really matter in life. I am sincerely
grateful to my sisters and the rest of our family members who tried to encourage me
despite the distance. Their persistent love and support have given me the strength to
persevereinreachingmyeducationalgoals.
Last, but not least, I would like to thank my wife, Pinky, for all her love and
companionship. It would have been very difficult to complete this work without her
presence. Being the person closest to me, she had to suffer through ups and downs
of Ph.D. studies, but she never stopped bringing my life joy and happiness, which I
neededthemost. MywifePinkyandtwolovelydaughtersShreeyaandSnehareceive
mydeepestgratitudeandloveallthetimefortheirinvaluablededicationandsacrifice
ineverypartofmylife.
A sad moment at the end was sudden death of my beloved grand father Chandra
Bahadur Thapa and father-in-law Shankar Raj Bista with whom I wanted to share all
myachievements. Idedicatethisworktothem.Contents
1 Introduction 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 OverviewofThesiswork . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 FundamentalsofIII-Nitrides 5
2.1 PhysicalPropertiesofGroup-IIINitrideMaterialSystem . . . . . . . . . 5
2.1.1 CrystallographicStructure . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.2 BandStructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.3 PolarizationEffects . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2 SubstrateMaterials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3 Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.4 GrowthTechniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.4.1 HydrideVaporPhaseEpitaxy . . . . . . . . . . . . . . . . . . . . . 26
2.4.2 PhysicalVaporTransport . . . . . . . . . . . . . . . . . . . . . . . 27
2.4.3 LiquidPhaseEpitaxy . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.4.4 PulsedLaserDeposition . . . . . . . . . . . . . . . . . . . . . . . . 27
2.4.5 MolecularBeamEpitaxy . . . . . . . . . . . . . . . . . . . . . . . . 28
2.4.6 MetalOrganicVaporPhaseEpitaxy . . . . . . . . . . . . . . . . . 29
2.5 CharacterizationMethods . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3 MetalOrganicVaporPhaseEpitaxy 34
3.1 BasicPrincipleofMOVPE . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.2 PrecursorsandChemistryofEpitaxialGrowthofAlN . . . . . . . . . . . 37
3.2.1 Precursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.2.2 ChemistryofEpitaxialGrowthofAlN . . . . . . . . . . . . . . . . 39
3.3 MOVPE-SystemAIXTRONAIX200RF . . . . . . . . . . . . . . . . . . . 41
3.4 In-SituCharacterizationinMOVPE . . . . . . . . . . . . . . . . . . . . . . 44
4 MOVPEGrowthofAlN 47
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.2 Two-stepGrowthProcessonSapphire . . . . . . . . . . . . . . . . . . . . 48
4.2.1 Desorptionandnitridationofsapphire . . . . . . . . . . . . . . . 48
4.2.2 Medium-temperaturenucleationlayer . . . . . . . . . . . . . . . . 50
4.2.3 StagebetweenNucleationandEpitaxialLayers . . . . . . . . . . 57
4.2.4 HighTemperatureEpitaxialLayer . . . . . . . . . . . . . . . . . . 59
iContents
4.3 StructuralandSpectroscopicPropertiesofAlN . . . . . . . . . . . . . . . 72
4.4 Multi-stepgrowthonsapphire . . . . . . . . . . . . . . . . . . . . . . . . 83
4.5 UsingIndiumasSurfactant . . . . . . . . . . . . . . . . . . . . . . . . . . 88
4.6 In-situdepositedSiN asdefect-reducinginterlayer . . . . . . . . . . . . 90x
4.7 AlNonDifferentSubstrates . . . . . . . . . . . . . . . . . . . . . . . . . . 93
4.7.1 GrowthonSiC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
4.7.2 Growthonnativ